Monarch-MoE: Structured Experts for Multimodal Continual Instruction Tuning
On the map: Mixture-of-experts → Mixture of LoRA experts
Abstract (arXiv)
Learning new tasks in multimodal continual instruction tuning can cause catastrophic forgetting of previously acquired knowledge. Although multi-expert LoRA distributes learning across experts, updates to a dense low-rank expert can still affect many output features. We introduce Monarch-MoE, which replaces the dense factors in LoRA experts with block-diagonal factors connected by a fixed permutation. This structure provides blockwise gradient isolation: individual block-pair updates affect only one output block, while connections between all input and output blocks are maintained. To make these compact experts practical on memory-limited hardware, we combine batched computation, fused forward operators, and an optimized backward pass. Across three continual-learning methods evaluated on MLLM-DCL and UCIT with LLaVA-1.5-7B, Monarch-MoE improves first-task retention while reducing adapter parameters by approximately 75% and 50%, respectively. In the main comparison, first-task forgetting is as low as 0.52 percentage points on MLLM-DCL and 0.10 on UCIT, with method-dependent trade-offs in final performance. Our implementation supports fine-tuning and inference on a single 24 GB RTX 4090, with lower measured memory use and competitive runtime in the evaluated settings. Together, these algorithmic and systems improvements make structured experts a practical option for continual adaptation on memory-limited hardware.
Key facts. No citing papers in the map yet (data through 14 Oct 2026). Placed in Mixture of LoRA experts, one of 12 directions in Mixture-of-experts. Builds on 13 of its 13 references that are in the map. First posted on arXiv 9 Oct 2026.
Builds on
13 of 13 references.
References · 13
- 2021LoRA: Low-Rank Adaptation of Large Language Modelscited by 14,380
- 2016Overcoming catastrophic forgetting in neural networkscited by 4,787
- 2023Improved Baselines with Visual Instruction Tuningcited by 4,418
- 2019Similarity of Neural Network Representations Revisitedcited by 1,755
- 2024DoRA: Weight-Decomposed Low-Rank Adaptationcited by 758
- 2023Orthogonal Subspace Learning for Language Model Continual Learningcited by 312
- 2022Monarch: Expressive Structured Matrices for Efficient and Accurate Trainingcited by 106
- 2024CoIN: A Benchmark of Continual Instruction tuNing for Multimodel Large Language Modelcited by 61
- 2025CL-MoE: Enhancing Multimodal Large Language Model with Dual Momentum Mixture-of-Experts for Continual Visual Question Answeringcited by 37
- 2025HiDe-LLaVA: Hierarchical Decoupling for Continual Instruction Tuning of Multimodal Large Language Modelcited by 31
- 2025MCITlib: Multimodal Continual Instruction Tuning Library and Benchmarkcited by 13
- 2025Federated Continual Instruction Tuningcited by 12
1 more
- 2024MoRe Fine-Tuning with 10x Fewer Parameterscited by 2
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- 2026CoRe-MoE: Compact Reusable MoE for Continual Multimodal Instruction Tuning
- 2025Multimodal Continual Instruction Tuning with Dynamic Gradient Guidance
- 2026CRAM: Centroid-Routing and Adaptive MoE for Multimodal Continual Instruction Tuning
- 2025Enhancing Multimodal Continual Instruction Tuning with BranchLoRA
- 2026PASs-MoE: Mitigating Misaligned Co-drift among Router and Experts via Pathway Activation Subspaces for Continual Learning
- 2025LoRA in LoRA: Towards Parameter-Efficient Architecture Expansion for Continual Visual Instruction Tuning
- 2026CP-MoE: Consistency-Preserving Mixture-of-Experts for Continual Learning
- 2024SwitchCIT: Switching for Continual Instruction Tuning